1. Field of the Invention
The present invention relates to rotary material removing tools, and more particularly to a drill having a pair of forwardly mounted cutting inserts, each cutting insert being set at a predetermined angle with respect to the center axis of the drill so that selected portions of each cutting edge of each cutting insert make progessive contact with a workpiece so as to facilitate material cutting and chipping during a drilling operation thereon.
2. Description of the Prior Art
It is well known in the prior art to construct rotary material removing tools, or drills, of general cylindrical shape. One end of the drill, designated herein as the rearward end, is structured to removably interconnect with a torque transmitting machine, such as a drilling, boring or milling machine. The other end of the drill, designated herein as the forward end, is structured to carry a removably mounted cutting tool bearing a pair of diametrically opposed cutting edges. These cutting edges physically contact the workpiece so as to perform the actual material removal therefrom. The forward end of the drill is more particularly structured with a slot oriented transverse to the center, or cylindrical, axis of the drill for receiving the cutting tool, and bores are provided in both the cutting tool and the slot for receiving screws for retaining the cutting tool in the slot. The drill is still more particularly structured to include grooves adjacent each cutting edge, each groove extending a predetermined distance parallel to the center axis of the drill from the respective cutting edge. These grooves serve to facilitate material removal as the drill engages the workpiece. An example of such a drill is described in U.S. Pat. No. 4,493,596 to Grunsky et al., dated Jan. 15, 1985.
While it is the case that the aforesaid drill is effective at removing material, there remains the problem of efficient removal of material during the drilling operation. Accordingly, what is needed is a drill which is structured for both effective cutting of material and efficient removal of the cuttings during the drilling operation.